Unless otherwise indicated herein, the elements described in this section are not prior art to the claims and are not admitted to be prior art by inclusion in this section.
User equipment (UE) devices, such as cell phones and wireless personal digital assistants (PDAs), are operable to communicate with radio access networks, such as cellular wireless networks. These UE devices and access networks typically communicate with each other over a radio frequency (RF) air interface according to a wireless protocol such as 1x Evolution Data Optimized (1x Ev-DO), perhaps in conformance with one or more industry specifications such as IS-856, Revision 0, IS-856, Revision A, and IS-856, Revision B. Other wireless protocols may be used as well, such as Code Division Multiple Access (CDMA), Global System for Mobile Communications (GSM), Time Division Multiple Access (TDMA), or some other wireless protocol.
Access networks typically provide services such as voice, text messaging (such as Short Message Service (SMS) messaging), and packet-data calls, among others. Access networks typically include a plurality of base transceiver stations (BTSs), each of which provides one or more coverage areas, such as cells and sectors (i.e., individual areas of a cell that allow the cell to carry more calls). When a UE device is positioned in one of these coverage areas, it can communicate over the air interface with the BTS, and in turn over a signaling network or a transport network, or both. The signaling network may be a circuit-switched network, a packet-switched network or a combination of both. Similarly, the transport network may be a circuit-switched network, a packet-switched network or a combination of both.
UE devices and access networks may conduct calls (e.g. voice calls and data calls) over a pair of frequencies known as carriers, with a BTS of an access network transmitting to a UE device on one of the frequencies, and the UE device transmitting to the BTS on the other. This is known as frequency division duplex (FDD). A BTS-to-UE-device communication link is known as the forward-link, while a UE-device-to-BTS communication link is known as the reverse-link.
UE devices may be configured with a particular radio configuration (RC) from among a plurality of RCs defined for a wireless protocol. Each RC can define a combination of forward and reverse traffic channel transmission formats based on, for example, data transmission rates, error-correction codes, modulation characteristics, and spreading factors. The RCs can, for example, be identified as RCX, where X is a positive integer.
UE devices may be mobile such that the UE devices can be transported between different coverage areas while the UE devices are operating in an idle mode (e.g., a mode in which the UE devices are not carrying out calls) or an active mode (e.g., a mode in which the UE devices are carrying out calls). A given coverage area provided by an access network may reach a capacity for carrying out calls if too many UE devices are carrying out and/or are trying to carry out calls while in the given coverage area. An access network may be arranged to compensate for coverage areas operating at their capacity.